The present disclosure pertains to a décor paper and paper laminates made from such paper. More specifically, the décor paper comprises a treated inorganic core particle, in particular a treated titanium dioxide particle, having improved opacity in highly loaded paper systems.
Paper laminates are in general well-known in the art, being suitable for a variety of uses including table and desk tops, countertops, wall panels, floor surfacing and the like. Paper laminates have such a wide variety of uses because they can be made to be extremely durable, and can be also made to resemble (both in appearance and texture) a wide variety of construction materials, including wood, stone, marble and tile, and they can be decorated to carry images and colors.
Typically, the paper laminates are made from décor paper by impregnating the paper with resins of various kinds, assembling several layers of one or more types of laminate papers, and consolidating the assembly into a unitary core structure while converting the resin to a cured state. The type of resin and laminate paper used, and composition of the final assembly, are generally dictated by the end use of the laminate.
Decorative paper laminates can be made by utilizing a decorated paper layer as the visible paper layer in the unitary core structure. The remainder of the core structure typically comprises various support paper layers, and may include one or more highly-opaque intermediate layers between the decorative and support layers so that the appearance of the support layers does not adversely impact the appearance of decorative layer.
Paper laminates may be produced by both low- and high-pressure lamination processes.
Décor papers typically comprise fillers such as titanium dioxide to increase brightness and opacity to the paper. Typically, these fillers are incorporated into the fibrous paper web by wet end addition.
In light colored and bright white décor paper applications, TiO2 concentrations of 30-45% by weight of pigment are needed to provide the desired color and/or opacity. However, at these high loading levels, the efficiency at which TiO2 functions as an opacifying agent deteriorates due to the “crowding effect” of the pigment. That is, twice the amount of pigment use based on a less concentrated paper system (i.e. one that comprises 20% TiO2 by weight), will not double the opacity in a highly loaded paper. In fact, the opacity fails short due to the crowding effect. Hence décor paper manufactures incur a cost penalty to reach the desired opacity in highly loaded white papers. Thus the need exists for a TiO2 pigment that can maintain its opacifying efficiency even in highly loaded paper systems.